John a



(MndeL) J. A. REED;

GOMPRESSIBLE OAST METAL PIPE.

-NQ 249,547. Patented Nov. 15,1881.

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UNITED STATES PATENT OFFICE.

JOHN A. REED, on NEW YORK, N1 Y.

COMPRESSI BLE CAST-METAL PIPE.

SPECIFICATION formingpart of Letters Patent No. 249,547, dated November15, 1881.

Application filed June 24, 1881. (Model) To all whom it may concern:

Be it known that I, JOHN A. REED, of the city and State of New York,(formerly of Dunellen, in the State ofNew Jersey,) have invented anImprovement in Compressible Cast- Metal Pipes, of which the following isa speci fication, I

Cast-metal tubes for boilers have been made with alternate bulges andcontractions, the section of the same being composed of segments ofcircles standin gin reverse positions. A tube of this character isrepresented in Letters Patent No. 192,389 grantedto me.

In my present invention the pipe is an ogee helix or spiral withcircular ends, and the same is especially adapted to the cast-iron fluesor water-tubes in furnaces, but the same may be placed at intervals insteam; gas, or water pipes or mains to allow for expansion andcontraction without injury to the tubes orjoints.

In the drawings, Figure 1 is a longitudinal section of this tube; Fig. 2is a cross-section a at the line as w, and Fig. 3 is an end view.

The sectionof each side of the tube is an undulatin g line or series ofogee curves, one standi ng in one direction and the other in the otherdirection. The convex curves are marked a and the concave curves aremarked 1), and they are of equal or nearly equal radius. The tube hasaconfiguration that would result from the revolution of the convex andconcave curves a 1) around the axis of thetube, at the same time that anend motion is given sufficient to produce a screw form.

In order to obtain a pipe that is reliable under the various changes oftemperature and compression, I make the pitch-line ofthe screw abouttwo-thirds the diameter of the tube and the depth of the depression(forming the helical groove around the pipe) about one-quarter of thediameter of the pipe, so as to obtain the requisites of stren gthandlightness. This tube can be compressed endwise to a considerableextent without injury, although made of castiron, and the ordinaryexpansion and contraction can take place without injury to the tube orto the joints by which the tube is connected; hence this tube is adaptedto the flues of boilers to contain water with the heat outside the tube,to use in water, gas, or steam mains or pipes, to allow of expansion orcontraction, and to other uses Where a compressible cast-iron tube canbe employed. At the ends of the tube the spiral terminates in a partialcylinder at d that forms a circular end to the tube, and has the axis ofthe tube for the center, otherwise the end of the tube would open at oneside, as indicated by thesection, Fig. 3 and to strengthen the end thereis either an outward or an inward flange, e.

I am aware that screw-shaped tubes have been made, but the convex andconcswe curves are'not equal, and hence the strain resulting fromcompression is not equal on all parts of the metal. Flanges have alsobeen employed at the ends of the tubes, and cylindrical ends to thescrew-shaped tubes have also been pro posed. In my improvement thecylindrical ends are contracted so as to be smaller than thescrew-shaped portion, and the extreme ends are flanged or thickened, theobject of this being to allow of the necessary strength of metal betweenone opening and the next in the tubesheets, against which the ends ofthe screwshaped tubes are received, and at the same time thescrew-shaped tubes can be arranged moderately close together, so as toget the maximum number of tubes into a. given space.

I claim as my invention- The cast-metal tube the body of which is anogee helix, the convex and concave curves bein g equal, or nearly so,and theends of the tube circular, of flanged or thicker metal, andsmaller than the screw, portion, but having the same axis, substantiallyas set forth.

Signed by me this 24th day of March, A. I).

GEo. T. PINoKNEY, HAROLD SERRELL.

